Donaldson A I, Kitching R P
Agricultural and Food Research Council, Institute for Animal Disease Research, Pirbright Laboratory, Woking Surrey.
Res Vet Sci. 1989 Jan;46(1):9-14.
Cattle vaccinated with a conventional monovalent type O1 foot-and-mouth disease (FMD) vaccine were challenged between four and 21 days after vaccination by short-term exposure to homologous airborne virus produced by pigs. Transmission was then assessed by housing susceptible cattle with the vaccinated animals and testing and observing all the animals for signs of infection and clinical disease. All 18 cattle vaccinated three weeks before challenge resisted clinical disease and although four contracted subclinical infection, there was no transmission to susceptible cattle in contact. One of the two groups of cattle vaccinated two weeks previously transmitted subclinical infection, but not disease, to susceptible animals housed with them from day 0 after challenge. Subclinical infection was manifested by a transient viraemia which was not followed by a detectable circulating antibody response. Shorter periods (seven or four days) from vaccination to challenge resulted in transmission of disease from clinically normal vaccinated to in-contact animals in one of two experiments. The severe challenge presented by the diseased in-contact animals than overwhelmed the immunity of the vaccinated animals. The results indicate that during emergency vaccination programmes it is advisable to vaccinate all FMD-susceptible animals within the vaccination zone and that at the outer boundary of the zone vaccinated animals should be kept separated from unvaccinated animals for at least three weeks.
用传统单价O1型口蹄疫（FMD）疫苗接种的牛，在接种后4至21天内，通过短期接触猪产生的同源空气传播病毒进行攻毒。然后，将易感牛与接种疫苗的动物圈养在一起，对所有动物进行检测并观察其感染迹象和临床疾病，以此评估病毒传播情况。在攻毒前三周接种疫苗的所有18头牛都抵抗了临床疾病，尽管有4头牛发生了亚临床感染，但并未将病毒传播给与之接触的易感牛。在攻毒前两周接种疫苗的两组牛中，有一组从攻毒后第0天开始，将亚临床感染而非疾病传播给了与之圈养在一起的易感动物。亚临床感染表现为短暂的病毒血症，之后并未出现可检测到的循环抗体反应。在两项实验中的一项中，从接种疫苗到攻毒的时间较短（7天或4天），导致临床正常的接种疫苗牛将疾病传播给了与之接触的动物。患病的接触动物带来的严重攻毒压力超过了接种疫苗动物的免疫力。结果表明，在紧急疫苗接种计划中，建议对疫苗接种区内所有易感口蹄疫的动物进行接种，并且在该区域的外部边界，接种疫苗的动物应与未接种疫苗的动物至少隔离三周。
